The administration of medicaments by inhalation is one of the most promising approaches in therapy that can be applied to a wide variety of diseases. The first inhaled medicaments were used for the treatment of diseases affecting the airways; however there has been an increased interest recently for the development of inhaled forms of medicaments that target various other diseases, such as diabetes.
The administration of medicaments by inhalation is carried out by using inhalation devices (inhalers). A large number of such devices are comprised in the state of the art. A large category of inhalers includes those wherein the medicament is situated in a receptacle in the form of dry powder and wherein the patient, by using the power of his/hers lungs, creates a streaming of air which carries along the powder which is subsequently inhaled through a mouthpiece. These devices are known as dry powder inhalers (DPIs). The powder in said devices is either situated in a container from where the required amount is measured using an internal mechanism, or it is packed as individual doses in the corresponding receptacles such as blister packs or capsules. The powder comprises the active ingredient which in most cases is combined with one or more excipients.
It is also known from the state of the art that some diseases are treated by a combination of more that one inhaled medicaments which, when this is possible, are preferably administered simultaneously. The simultaneous administration through the inhalation route is preferred over the sequential administration because in this way the patient receives the required dose of the medicaments by inhaling only once and therefore the treatment is achieved by the use of a single inhaler, something which solves many practical problems and results in better compliance by the patient. Furthermore in some cases the simultaneous administration may be proved to be therapeutically more effective comparing to the sequential administration. In the cases of simultaneous administration of a mixture of medicaments the inhalers are the same with the ones used for the administration of a single medicament, the only difference being that this time the pharmaceutical composition comprises the mixture of the active ingredients in the appropriate ratio which in the majority of cases is mixed with one or more excipients.
However, the presence of a mixture of active ingredients in the pharmaceutical composition creates considerable problems. First of all it is possible that an interaction between the active ingredients comprised in the mixture may occur, which may result in their decomposition. This outcome in the best of cases leads to the decreased effectiveness of the treatment as a result of the presence of smaller amounts of the active ingredients in each dose, whereas in the worst cases it may become hazardous for the patient since the decomposition products could not only be therapeutically ineffective but pose a danger to the patient's health. Furthermore, the presence of a mixture of active ingredients creates problems with the development of the appropriate pharmaceutical composition, since each active ingredient has its own physical and chemical characteristics which are not necessarily compatible with the corresponding characteristics of the other ingredient. Consequently, the development of a pharmaceutical composition which is suitable for both ingredients of the mixture becomes more difficult.
One of the dry powder inhalers comprised in the state of the art is that disclosed in WO03082389. Said document discloses a dry powder inhalation device wherein the medicament is packed in the blister of a specially designed single dose blister strip. The device comprises a mouthpiece, a blister strip support surface and a strip storage compartment. The support surface comprises an attachment point (e.g. a protrusion), a cavity which receives the blister of the strip and guides for the correct placement of the strip. The three parts are movably joined to each other. When the blister strip is placed on the support surface and the mouthpiece is in its basic position, the base of the mouthpiece touches the strip and covers completely the powder containing blister.
The mouthpiece of said device comprises three parts, an exterior part and two interior parts of conical shape. The first of the interior parts, whose lower side has two openings and touches the blister of the strip, is divided into two chambers through which the air which enters the mouthpiece carries the powder. Then, the mixture of air and powder passes through the second interior part of the mouthpiece and exits the device.
In order to use said device for the simultaneous administration of a combination of medicaments, the single dose blister strips should contain the mixture of said compounds, with all the aforementioned problems and disadvantages.
The present invention enables the user to inhale simultaneously a combination of two medicaments, while it provides solutions to all of the above-mentioned problems.